The department is working with state agencies, local governments and other stakeholders to undertake the Brisbane River catchment studies. Our partners in this important flood management project include:
- Department of Energy and Water Supply
- Department of Environment and Heritage Protection
- Department of Natural Resources and Mines
- Department of Science, Information Technology, and Innovation
- Brisbane City Council
- Ipswich City Council
- Lockyer Valley Regional Council
- Somerset Regional Council
This work supports the findings in the Queensland Floods Commission of Inquiry final report released in 2012. Specifically, the department is addressing recommendation 2.2 in Chapter 2 of the report.
Wivenhoe and Somerset Dams Optimisation Study
As the first output from the Brisbane River catchment studies, the Queensland Government completed the Wivenhoe and Somerset Dams Optimisation Study in 2014. This study presented options for improving the use of existing dam infrastructure to deliver better flood mitigation outcomes ahead of the 2014-15 summer wet season, without putting future water supplies at risk.
Under the adopted operational strategy, more flood water will be released earlier from Wivenhoe Dam to increase water storage space in case a large flood eventuates. While this may result in some crossings, like Colleges Crossing in Ipswich, being closed more regularly, it will mean that fewer buildings (around 500 to 1500) may be affected in Brisbane and Ipswich if a flood of a similar magnitude to 2011 was to occur.
Brisbane River Catchment Flood Studies (BRCFS)
The department is playing an important role, in partnership with other state agencies and the four local government councils, in preparing for future flood events through the technical Brisbane River Catchment Flood Study and the Brisbane River Catchment Floodplain Management Study. The recommendations from this study will form the basis of catchment-wide and local area specific floodplain management plans.
The flood study
The flood study is well underway and will deliver comprehensive models of the river catchment. The study builds on the existing work undertaken by the Brisbane River catchment councils, Seqwater and the State Government.
This study involves a hydrologic assessment (now complete) and a hydraulic assessment (currently underway). The hydrologic assessment informs the hydraulic assessment, which will be completed in February 2017.
Together these assessments aim to deliver consistent, up-to-date technical flood data for local governments and other users across the Brisbane River catchment to help better plan for and minimise the impacts of future floods.
Brisbane River Catchment Floodplain Management Study
The Brisbane River Catchment Floodplain Management Study (BRCFMS) will identify floodplain risks and assess various flood mitigation and management measures to increase the community's resilience to floods in the Brisbane River catchment (including the Bremer River, Lockyer Creek and smaller tributaries).
The recommendations from the BRCFMS will form the basis of catchment-wide and local area specific floodplain management plans to be used by the state and councils. This will enhance government and community ability to better respond to rainfall events. The study is due for completion in late 2017.
Catchment-wide and local area specific floodplain management plans will be used by state government and the four catchment area councils to prioritise a range of infrastructure projects and guide land use planning to better manage residual flood risks. The plans will assist councils in updating sub-catchment plans to ensure their communities are informed, ready and resilient.
The final management plans will be important tools to help protect Queenslanders from future flood events so it is important that they are technically robust and achieve best practice outcomes for many years to come. The plans will take some time to finalise and are likely to be released in 2018.
In the meantime, state and local governments will use an interim disaster management modelling tool that was developed in 2013 as part of the flood studies in the event of flooding rain.
To obtain further information on the Brisbane River Catchment Study, including purpose, methodology and timing, please read our Understanding the Brisbane River Catchment Flood Study ( 369 KB) fact sheet. For more details about the hydrologic and hydraulic studies, please read our Brisbane River Catchment Floodplain Study ( 616 KB) brochure.
National flood risk advisory group
The department is the Queensland Government's coordinating agency on the National Flood Risk Advisory Group (NFRAG) that is a reference group of the Australian and New Zealand Emergency Management Committee.
An important part of our role on this advisory group has been involvement in the preparation of a new national floodplain manual considerate of Queensland conditions. This work is in response to recommendations 2.20 and 2.21 of the Commission of Inquiry report. The 'Managing the floodplain: a guide to best practice in flood risk management in Australia – AEMI Handbook 7' (2013) is available for free download or purchase on the Australian Emergency Management Institute website.
Flood risk management
Effective flood risk management should take into account that risk does not remain constant. The likelihood and consequences of risk can change significantly with increases in catchment and floodplain development and due to changes to infrastructure in the floodplain.
Flood risk management has been shown to have great benefit in reducing risk through:
- improvements in strategic land use planning and building controls
- implementation of structural works to reduce flood impacts
- development of flood warning systems
- emergency management planning
- public education programs.
The Queensland Government is supporting a new way of thinking about flood events and a more risk-based approach using flood probabilities (Annual Exceedance Probability [AEP]). The traditional Q100 (1 in 100 year flood level) terminology is no longer being used as it can suggest a fixed time recurrence interval between flooding events, which is not the case in reality. Neither does that terminology convey the full range of more extreme floods that may occur. The following table compares the average recurrence interval with the statistical probability of a range of flood events occurring in an 80-year lifetime:
|Annual Exceedance Probability||Average recurrence interval||Probability of Experiencing in an 80 year period|
|at least once||at least twice|
|20%||1 in 5 years||100%||100%|
|10%||1 in 10 years||99.9%||99.8%|
|5%||1 in 20 years||98.4%||91.4%|
|2%||1 in 50 years||80.1%||47.7%|
|1%||1 in 100 years||55.3%||19.08%|
|0.5%||1 in 200 years||33.0%||6.11%|
|0.2%||1 in 500 years||14.8%||1.14%|
|0.1%||1 in 1,000 years||7.69%||0.30%|
Natural hazards management guides
The state's land use planning interest in relation to natural hazards is: "The risks associated with natural hazards are avoided or mitigated to protect people and property and enhance the community's resilience to natural hazards."
Further information regarding the state's interest in natural hazards, and supporting guidance, is available in the following documents:
- State Planning Policy ( 2.1 MB)
- State interest - natural hazards, Guidance on flood, bushfire and landslide hazards ( 1.54 MB)
Queensland Reconstruction Authority
On 21 February 2011, the Queensland Reconstruction Authority was formed under the Queensland Reconstruction Authority Act 2011. The Authority's role has been extended to cover historical and continuing disaster events in Queensland. The Authority's current mission is to reconnect, rebuild and improve Queensland, its communities and economy.
The Authority reports to the Deputy Premier, Minister for Transport, Minister for Infrastructure, Local Government and Planning and Minister for Trade Jackie Trad MP, and also to the Queensland Reconstruction Authority Board (the Board).
The Authority manages and coordinates the Government's program of infrastructure reconstruction within disaster affected communities.
The Authority has published various guides in relation to floodplain management. For enquiries about these documents and reconstruction activities please contact the Authority.